The use of a magnetic field to levitate a diamagnetic material is known in the prior art. Superconducting magnets have been used to levitate diamagnetic objects such as water, frogs, pyrolytic graphite plates, and the like. The classic superconducting magnetic coil design cannot be used to create a magnetic levitation playing field in a stadium or arena because the huge magnetic field that is produced is not self-terminating. If a classic superconducting magnetic coil design were used in a stadium or arena the local magnetic north pole would be shifted in the surrounding area and might alter local air traffic and vehicle compasses. Magnetic strips or smart phone memory of spectators in the stadium or arena would be erased and any metallic items such as keys, spoons, knives, and supports in shoes would be immediately attracted to the field surface.
The most popular scientific demonstration model of magnetic levitation uses a plate of pyrolytic graphite or super conducting metal and a 4 by 4 array of strong ceramic magnets setup in a checker board pattern (N-S-N-S by S-N-S-N). This checker board pattern creates huge magnetic flux gradients across each square because the magnetic field lines are bent 180 degrees to enter or exit each ceramic magnetic piece both at the top and bottom of the magnetic array.
At 3 times the dimension of the side of the square magnet, the magnetic field strength from the checker board design is almost zero even with a magnetic field strength of 16 Tesla. An important characteristic of this design is near zero field strength decay, eliminating the need for magnetic shielding of spectators in a stadium or arena. The magnetic field is self-terminating so spectators in a stadium or arena would not be affected by the magnetic field.
U.S. Pat. No. 6,850,137 discloses an apparatus and method for levitating a diamagnetic material using a magnetic field produced by a superconducting magnet. Concentric superconducting coils produce magnetic fields when energized with current. The magnetic fields of the coils combine to produce an operational magnetic field for levitating the diamagnetic material inside a central bore.
U.S. Pat. No. 8,317,682 and U.S. Patent Application 2010/0036394 demonstrate how to use a three dimensional magnetic field to control the movement of a diamagnetic medical device. A strong magnetic field parallel to the gravitational force is used to levitate the medical device in space while smaller magnetic fields perpendicular to the gravitational force are used to overcome drag force of moving the medical device inside a body cavity. Even smaller alternating electromagnetic fields are used to locate the position and orientation of the device in the body and for communication with sensors on the device.
U.S. Pat. No. 6,162,364 discloses a system for diamagnetic manipulation of an object in a surrounding medium in a low gravity environment. If a diamagnetic object is suspended in a fluid that has a lower diamagnetic value than the object, it can move away from the electromagnet when the magnet is turned on. Thus, with a plurality of electromagnets, the position and orientation of the object can be controlled in space.
U.S. Patent application 2006/0162452 discloses an inertial sensor based on diamagnetic levitation. The inertial sensor has a support means and a two dimensional array of permanent magnets. A diamagnetic element faces the array of magnets and through diamagnetic levitation the diamagnetic material constitutes the inertial sensor.
U.S. Pat. No. 8,360,999 discloses a method for suspending a plate to generate vibrations in the plate at approximately 35 Hz with a magnitude of 0.5 g. The plate is suspended with permanent magnetic levitation and the vibrations are created with electromagnetic repulsion and attraction. The method can be used for the treatment or prevention of musculoskeletal indications.
At present, there are no suitable diamagnetic levitation system designs for large playing fields to produce weightless simulation for use in stadiums, arenas, superdomes, theaters, universities, and the like